Purpose. In contrast to incisional keratotomy, refractive techniques such as automated lamellar keratectomy (ALK) and excimer photorefractive keratectomy (PRK) are difficult to detect. Cadaveric corneas with high refractive myopic correction may result in substantial post-operative hyperopic correction if used for corneal transplants. Displacement of the treated optical zone within the graft could also result in induced astigmatism and distortion. This study examined the potential of videokeratographic (VKG) analysis of cadaveric whole globes to determine if topography may be a useful screening strategy for detecting PRK. Methods. A vertically mounted videokeratoscope from "EyeSys Technologies" was used to determine corneal topography of cadaveric corneas of whole globes. Both 5 mm and 6 mm PRK ablation zones were performed using an OmniMed excimer system with myopic corrections of 6, 5, 4, 3, 2 and 1.5 diopters. Results. VKG could reliably detect PRK on cadaveric corneas at all tested myopic corrections. Myopic ablations yielded a "bullseye" topography pattern when the data was processed in the tangential map mode. Profile maps of the 0-180 and 90-270 axes were also useful in analyzing results. Conclusions. VKG may be a useful method to screen donor globes for PRK. The method is not amenable to screen donor corneal scleral rims and is therefore limited to whole globes. Studies of excimer treated rabbit corneas confirm PRK can be detected on enucleated globes 6 weeks post surgery.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience